This invention relates to a switching device such as a microswitch or the like, which is secured on a web of associated switch apparatus.
Currently known microswitches utilize housings which have through-bore fastening holes so that this switch can be secured on a web of a support by means of a screw. The diameter of the screw is smaller than the diameter of the fastening hole so that the switch is not rigidly fastened on the web at least when the screw is not tightened firmly. Due to the fact that the switch housing is usually made of plastics material and in order not to damage the switch housing the screw cannot be tightened to the extent required. Further, the mounting of a fastening screw is relatively complicated and time-consuming. Similar disadvantages occur when a rivet is used as a fastening element instead of the screws. Also here the switch can be slightly displaced relative to the support when acted upon by a larger force, because the tolerance of the diameter of the rivet shaft has to be smaller than the diameter of the fastening holes.
Therefore it can be stated that in the prior art the switch is not secured on the support in a sufficiently stable manner. If this switch is actuated by an adjusting member which is displaceably mounted relative to the support, the switching points of the switch change, if the switch is displaced relative to the support in the switching direction.
The invention is therefore based on the problem of creating a fastening for a switch of this kind in which permits an easy mounting and at the same time endures larger forces acting upon the switch, so that the switch is held in exactly the prescribed position even after extended service periods and thus the switching points remain within the given tolerances.
At first it is essential for the present invention that now the fastening element is supported on both sides of the switch. Thus tilting movements of this fastening element transversely to its axis are prevented which would be possible with the known embodiments when, for example, the screw connection would be slightly loosened. Furthermore it is essential for the present invention that the fastening element is pressed with press-fit both in the receiving bores of the two webs and in the fastening hole of the switch housing. Thus tilting movements of the switch relative to the axis of this fastening element are also prevented. Moreover, the design of the present invention has the advantage over the prior art that the assembly is considerably simplified.
The fastening element as such is also clearly secured in the axial direction by the intended press-fits. Nevertheless it can happen that, upon exertion of great forces, the switch is displaced in the axial direction of this fastening element. This deficiency can be cured by providing compensating ribs on a wall of the switch housing or on a web, so that the switch housing is so-to-speak seated with press-fit between the two webs. Alternatively or additionally the switch housing can, in an advantageous development according to the invention, be clamped between the first web and a first portion of the fastening element, when the fastening element is reliably secured against displacement in the axial direction. This can, for example, be realised in that holding ribs are formed out of the web, which holding ribs are pressed on the free front surface of the fastening element.